Experimental Investigation of Shear Strength Parameters of Rubber-Coated Ballast

Covering ballast aggregates with rubber particles is referred to in the literature as rubber-coated ballast (RCB). Although this approach reduces the abrasion and crushing of the ballast and increases its damping, the effect of RCB mixing with traditional ballast on the shear strength and the track lateral resistance has not been considered. To investigate this issue, the abrasion behavior of this mixture has been tested by performing Los Angeles and micro-Deval experiments. The next step involves an examination and study of the shear strength, dilation angle, internal friction angle, and cohesion coefficient under three normal stresses of 0.05 MPa, 0.1 MPa, and 0.15 MPa. The results showed that by adding RCB of 25%, 50%, 75%, and 100% (by weight) to the common ballast, the amount of Los Angeles abrasion on average decreased by 51.9% while the amount of micro-Deval abrasion on average decreased up to 25%. Compared to the common ballast, the maximum shear stress of the RCB samples decreased by 0%, 23.08%, 38.46%, and 42.31%, respectively, at 0.15 MPa. Furthermore, in the sample containing 100% RCB, the dilation angle and internal friction angle decreased by 40.5% and 52.39%, respectively, while the cohesion coefficient showed a significant increase of up to 250%.